Problem with To and CC fields being rewritten

I am a procmail neophyte, yet I made the mistake of installing procmail as
our mail delivery agent on our mailhub which gets mail for over 20,000
users. My problem is this (sorry if this is a FAQ but I couldn't find it):

        The To, CC Bcc etc fields are all being rewritten by procmail and the
domain of the address is being stripped out. This causes problems when users
try to reply to these messages, since the addresses of the users in the cc
fields etc. are not fully qualified addresses, their mail is not delivered
properly.

We have a central mailhub that knows how to handle delivery of mail to our
domain and the machines that the users use to read and send mail from do not
know how to deliver to our domain properly.

I imagine that this must be a common problem, and is probably fixed by some
configuration parameter but I am unable to find which one.

By the way I am running sendmail 8.6.12 and procmail-3.11pre4, we are not
using any system procmailrc files.

I would like a solution that was compiled into procmail as I imagine it would
be more efficient (we handle over 30,000 messages a day on this machine).

Thanks for your time.


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Avalon Johnson                                   Usenet:   
avalon(_at_)yorku(_dot_)ca
Computing & Communications Services
York University.